Theodor Seuss Geisel, best known as his pseudonym, Dr. Seuss, is one of the most popular children's authors of all time. He wrote and illustrated over 44 books, plus wrote over a dozen other books under his other pseudonyms Theo LeSieg and Rosetta Stone, which were illustrated by others. His books have sold over 222 million copies and been translated into more than 15 languages. His books are favorites for many children, and are best known for his imaginative characters and rhyme.